<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script type="text/javascript">
    let a;
    let arr1 = [1,2,3];

    a = ...arr1;
    //a=1,2,3;
    alert(a);

    </script>
  </head>
  <body>

  </body>
</html>
